洞庭湖区的气温特征及其对湖南气温分布的影响

The Temperature Characteristic of Dongting Lake Region and Its Effect on Temperature Distribution in Hunan Province

利用1971—2000年湖南95个气象站30年气候整编资料及2003—2004年湖南部分气象站逐时资料,系统地分析了洞庭湖区气温的分布特征及其对全省气温分布的影响,揭示出:年平均气温在湖区东部呈现出一个暖舌;洞庭湖改变了气温通常的南高北低分布态势,使湖南的月平均气温分布还呈现出了东高西低型和过渡调整型;湖区是最高气温分布的低值区,最低气温分布的高值区,气温日较差偏小;相对于省内同经度和同纬度区域,湖区的月平均气温日较差偏小,尤其是在夏半年差距更为明显,且在7月份出现了反位相,气温日变化曲线较平稳,日最高气温出现时间约迟2小时,在同一种天气条件下,湖区气温日变幅总是偏小,不同天气条件下,日最高气温的差值和日最低气温的差值表现为晴天最大、阴天次之、雨天最小。

According to the 30a climatic data about 95 stations of Hunan Province from 1971 to 2000, and the data hour by hour about part of observation stations in Hunan from 2003 to 2004, this paper analyses Dongting Lake＇ s effect on temperature to surrounding areas and the whole province, the results show that： the yearly mean temperature in the eastern part of the lake region shows a warm tongue. Dongting Lake changes the usually distribution trend of Hunan province that the temperature in the south is higher than in the north, so that the monthly mean temperature in Hunan also shows distributions of East- West and transition. The lake district isthe low- value areas of highest temperature, and the high - value of minimum temperature, daily range of temperature is lower. Compared to the same latitude and longitude regions of the province, and latitude of Hunan, the monthly mean daily range of temperature in the lake district is lower, particularly in the summer half year, in July it appears in the antiphase, the temperature curve is more stable, and the daily maximum temperature appears 2 hours later, in the same weather conditions, the temperature amplitude of variation is always a little smaller, but under different weather conditions, the difference of the daily maximum temperature and the difference of the daily minimum temperature are largest in sunny days, smaller in cloudy days and smallest in rain days.